CHARLESTON — Voters will decide Tuesday whether to help former Gov. Mark Sanford in his quest for political redemption or to make former Charleston County councilman Curtis Bostic the GOP nominee for an open South Carolina congressional seat.


Sanford and Bostic were the top two finishers in a 16-way Republican free-for-all in the 1st District on the state’s south coast two weeks ago.


The winner of the runoff advances to face Democrat Elizabeth Colbert Busch and Green Party candidate Eugene Platt in the May 7 special election.


The seat, held by Sanford for three terms during the 1990s, became vacant last year when Gov. Nikki Haley appointed sitting congressman Tim Scott to fill the U.S. Senate seat in turn left vacant by the resignation of Jim DeMint, who left Congress to join a conservative think tank.


Sanford is trying to rebuild his political life after disappearing from the state four years ago only to return and confess he was having an affair with an Argentine woman to whom he is now engaged.


Bostic, a former Marine and an attorney who operates a couple of charities, said during a debate last week that Sanford’s behavior has left him a compromised candidate. If Sanford is nominated, Bostic warned, it could open the door to the Democrats regaining a seat they have not held in more than 30 years.


The latest finance reports filed with the Federal Election Commission show Sanford has a prohibitive edge in fundraising. He has raised $413,000 to about $92,000 for Bostic, who has also loaned his campaign $150,000. Sanford has not loaned his campaign any money.


Those reports show Sanford, known for his frugality both as congressman and governor, has spent only $15,000 on the campaign whose trademark has been supporters scrawling campaign messages with spray paint on pieces of wood and setting them along the district’s roadways.


Both candidates spent the last day before the runoff meeting voters at shops and restaurants in the southern end of the district where they were to attend a forum on Hilton Head Island.


About 12 percent of the district’s 454,000 voters cast ballots in the GOP primary two weeks ago.


Chris Whitmire of the South Carolina State Election Commission said turnout Tuesday could be slightly higher because in past primaries, runoff turnout has increased especially in races were the original field was crowded.


All registered voters in the district can cast ballots Tuesday except those who voted in the Democratic primary two weeks ago.